Chiari I malformation with cervical syrinx presenting with progressive left arm weakness and vocal cord palsy

BACKGROUND: Chiari I malformation with associated cervical syrinx represents an uncommon but important central neurological cause of unilateral vocal cord palsy that should be considered when no primary laryngeal or peripheral aetiology is identified.CASE PRESENTATION: We report the case of a 28-year-old man presenting with left unilateral vocal cord palsy and progressive left arm weakness. Subsequent investigation identified a Chiari I malformation and associated cervical syrinx extending from C2 to C5, with cerebellar tonsillar herniation of 6 mm below the foramen magnum confirmed on MRI. In the absence of a primary laryngeal lesion or peripheral cause, a central neurological aetiology was pursued at the initiative of the ENT team, ultimately leading to a neurosurgical referral for foramen magnum decompression. Written informed consent was obtained from the patient for publication of this case report and any accompanying images.CONCLUSIONS: This case underscores the importance of including central neurological pathology - particularly Chiari I malformation with syrinx - in the differential diagnosis of otherwise idiopathic unilateral vocal cord palsy, and highlights the pivotal role of ENT-led systematic evaluation and multidisciplinary collaboration in reaching a timely diagnosis.